Ready-to-eat ("R-T-E") breakfast cereals are popular packaged food items. R-T-E cereals exist in large numbers of varieties including puffed and unpuffed, natural or presweetened, and including a wide variety of cereal compositions. While certain problems are general to all varieties of breakfast cereals, some problems are specific to particular categories of products. In particular, some problems result from the selection of individual ingredients for incorporation into the cereal composition.
Whole grain based R-T-E cereal compositions have long been popular, especially oats. In view of the growing awareness of the health benefits to people associated with consumption of soluble fiber and the contribution to soluble fiber consumption that oat and oat fiber-containing compositions can provide, there is a growing interest in R-T-E cereals formulated to comprise an oat component.
Unfortunately, however, a significant problem associated with an oat based ready-to-eat cereal, especially puffed cereals, is the stability characteristics associated with the oat component. Generally, these stability problems are due to the relative instability of oat materials. Furthermore, these problems are aggravated by oat-based R-T-E cereals having higher fat levels than other R-T-E cereals. As the finished oat-based cereal ages, the cereal develops a characteristic and undesirable off-flavor. This deterioration is observable both by organoleptic/hedonic testing as well as by analytical testing. Unfortunately, the off-flavor development is auto catalytic and thus once started rapidly increases. The upper concentration of protective antioxidants is limited by regulation. As a result, oat based R-T-E cereals have an additional potential mode of failure than other R-T-E cereal compositions which do not contain high fat contents. Other whole grain based R-T-E cereals having high native fat contents, e.g., corn and barley, can share this problem if formulated to include significant levels of their oil bearing germ fraction. While other whole grain R-T-E cereals also experience stability problems, these problems with oat based cereals are notoriously severe.
If aged product reaches consumers, many consumers will react negatively to the undesirable associated off-flavor development. In order to forestall negative consumer reaction, large quantities of finished R-T-E product must be discarded because of developing rancidity problems even with the best finished product inventory and distribution control system. Moreover, the production of cereal having stability problems is an especially acute problem associated with a commercial plant start-up. Indeed, a major reason for plant start-ups requiring extended start-up times is that plant operations are not considered stabilized until an R-T-E cereal is produced which does not develop premature flavor deterioration due to product instability.
Still another problem in cereal processing resides in flavor development. Many consumers prefer puffed cereals, and particularly oat containing puffed cereals. Moreover, consumers have become familiar with puffed oat based R-T-E cereal in complex shapes such as torroids or rings or other shapes such as stars. Such complexly shaped puffed cereals are generally prepared by gun puffing moist (e.g., 10% to 14% moisture) cereal pellets. While popular, many consumers enjoy the flavor of toasted cereals. Limited amounts of toasting can be imparted by the puffing gun but at a trade-off in lost throughput due to the increased residence times necessary to impart the toasted flavor. Unfortunately, it is difficult to evenly toast puffed R-T-E cereals after puffing (especially those cereal pieces having a complex shape) using conventional toasting equipment and methods. Generally, such known toasting techniques involve intense heating including radiant and/or conduction heating which involve heat transfer from the exterior of the piece inward. Due to the low density of puffed pieces which insulatively resists conductive heat transfer and due to complex shapes, undesirable scorching of the exterior surface can occur prior to the development of desirable toasted flavor by any significant weight of the interior of the cereal piece.
In view of the state of the art, there is a continuing need for improvements in the cereal processing art for preparing R-T-E cereals exhibiting increased stability.
Accordingly, it is an object of the present invention to provide improved cereal processing methods for the production of R-T-E cereals which exhibit increases in shelf stability.
It is another object of the present invention to provide improved cereal processing methods which can be used to prepare R-T-E cereals comprising an oat based cereal composition.
Accordingly, it is still another object of the present invention to provide a toasted, oat containing puffed R-T-E cereal which exhibits enhanced shelf stability.
Still another object of the present invention is to provide improved cereal processing methods which can be used to prepare R-T-E cereals which comprise oat components in addition to other farinaceous components.
Still another object of the present invention is to provide methods for cereal processing which can be readily practiced in present commercial cereal processing plants without requiring extensive modification of existing cereal processing processes or equipment.
Another object of the present invention is to provide cereal processing method improvements which can reduce the cost of cereal processing by reducing plant start-up time.
Another object of the present invention is to provide cereal processing methods which can provide improvements in product stability so as to allow the reduction or elimination of addition of stabilizers such as antioxidants to cereal compositions.
Surprisingly, the above objects can be realized and the present invention provides methods for dramatically increasing the stability of oat-based, especially puffed oat-based R-T-E cereals. The present invention involves subjecting the finished R-T-E cereal to a brief exposure to a high intensity microwave field. For sugar coated embodiments, the cereal base can be microwave heated prior to the application of the topical coating. In its product aspect, the present invention resides in finished products exhibiting enhanced shelf stability.